Fluid conduits such as gas pipes, sewer pipes and water pipes are susceptible to the build-up of rust and scale on the inner surface of the pipe. This may be caused by corrosion of the inner pipe surface and/or the deposit of accretions onto the pipe surface, such as lime or other deposits of solids, from fluids moving in the pipe. Over time, rust and scale accumulate inside the pipe, which reduces the volume of flow through the pipe. Corrosion and erosion also deteriorate pipe walls, ultimately causing pits, pinhole leaks and major leaks necessitating replacement of the pipe.
Restoration of existing pipes by pipe lining can extend the useful life of pipes and thus reduce the frequency by which pipes need to be replaced. Pipe lining also takes less time to complete and costs less than replacing pipes. It also does not require holes to be made in walls.
A known method of pipe restoration by pipe lining is to first clean the pipes by draining the pipes, blowing heated compressed air, first by itself to dry the pipes, and then carrying particles of abrasive material through the pipes to dislodge the build-up on the inner surface of the pipe. An epoxy coating is then applied to the interior walls of the pipes by using the heated compressed air to blow epoxy through the pipes. The smooth coat of epoxy fills in pits and pinhole leaks and protects the pipes from corrosion and erosion. If only pipe cleaning is desired, the step of blowing the epoxy through the pipes is omitted.
Where such a method of pipe cleaning or restoration is carried out on the water supply pipes in a building, such as an apartment building, compressed air supply hoses are used to deliver the compressed air to each apartment unit. The hoses are then connected to a pipe in the apartment, such as a hot or cold water pipe in the kitchen, and the compressed air is blown through that branch pipe into the hot or cold water riser to an end of the riser, usually in the basement of the building, where the pipe has been cut open to vent the compressed air carrying the abrasive material and dislodged build-up through a hose and into filter and then into the open air. To deliver the compressed air to each apartment unit, the compressed air supply hoses are typically run from an air compressor on the ground outside of the building to an apartment unit through a window or balcony door in every apartment unit. Alternatively, compressed air supply hoses are run through the staircases of the building and then through the front door of each apartment unit. Either of these alternatives is dangerous as it requires a door or window to the apartment to remain open and unlocked, leaving the tenant or occupant vulnerable to theft or other crime. Furthermore, running air supply hoses to each individual apartment unit is labour-intensive and expensive.